A Study Towards Iron-catalyzed Direct Functionalization Of Sp~3C-O Etheric Bonds And Synthesis Of Alkaloid(±)-Fasicularin

The thesis mainly consists of the following two parts:PartⅠ: iron-catalyzed direct functionalization of sp3 C-O ether bondsIt is highly desirable to develop efficient, convenient, and environmental friendly synthetic methods in organic chemistry. Compared with the corresponding halides, ethers have many distinctive advantages in the aspects of economy and environmental protection.Therefore, the construction of C-C and C-heteroatom bonds with direct functionalization of C-O ether bonds is a very attractive strategy in organic synthesis. However, the activation of C-O bonds of ether is a challenging work for chemists due to the relatively high bond dissociation energy of ether. In recent years, although the transition-metal catalytic activation C-O ether bond cleavage formation of C-C bond reactions have been made significant achievements, such as using aryl or benzyl ethers instead of corresponding halides in Suzuki and Kumada couplings. But most of the examples focus on the activation of sp2 C-O ether bonds, and there are few studies about benzylic or allylic sp3 C-O ether bonds cleavage conversion to C-C bonds. In this thesis, we develop a simple and efficient method for the synthesis of α-aryl nitriles and indane derivatives via iron-catalyzed selective activation of sp3C-O ether bond. The effects of the type, amount of catalyst as well as solvent on the reaction system are investigated by us. Under the optimized reaction conditions, the generality of this reaction are then investigated on a series of benzylic and allylic methyl ethers.PartⅡ A study towards synthesis of alkaloid(±)-FasicularinIt has been proved that Ascidians contain a particularly rich N-heteroatom tricyclic marine alkaloids, and these alkaloids has garnered much attention from chemists due to its novel chemical structure and unique biological activities. Fasicularin is a kind of marine alkaloid isolated from the ascidian Nephteis fasicularis, which has selective activity against a DNA repair-deficient organism and also shown to be cytotoxic to Vero cells. In this article,the structure features and synthesis strategy of fasicularin are analyzed by us. We designed a new approach to synthesize fasicularin which use an intramolecular nucleophilic reagent initiated acyliminium ion cyclization as key step and try to construct N-heteroatom tricyclic system with Single step. We respectively used alkenyl silicon compounds and enol compounds as intramolecular nucleophilic reagent extensive experimental studies. Although the expected N-heteroatom tricyclic structure has not been obtained in this synthetic work at last, we have got two meaningful compounds during the research. Through this study, wehave learned much valuable knowledge about not only acyliminium ions but also tricyclic marine alkaloids.